Refrigerating process and the apparatus applicable thereto



1932- A. SELIGMANN 1,870,265

REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETO Filed Aug.18. 1928 7 Sheets-Sheet 1 1932- A. SELIGMANN 1,870,265

REERIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETO Filed Aug.18. 1928 7 Sheets-Sheet 2 inn/ 3' Qmjgg Aug. 9, 1932. SEUGMANN 1,870,265

REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETO Filed Aug.18. 19 28 Sheets-Sheet s 1932- A. ssusumnn 1,870,265

REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETC Filed Aug.1a. 1928 7 Sheets-Sheet 4 1932- A. SELIGMANN 1,870,265

REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETO Filed Aug.18. 1928 7 Sheets-Shet 5 Aug. 9, 1932.

A. SELIGMANN REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETOFiled Aug. 18. 192B 7 Sheets-Sheet 6 Fig. 7

Aug. 9, 1932. sEuG N 1,870,265

REFRIGERATING PROCESS AND THE APPARATUS APPLICABLE THERETO Filed Aug.18. 1928 7 Sheets-Sheet 7 Patented Aug. 9, 1932 PATENT OFFICE ARTHURSELIGMANN, F DUSSELDORF, GERMANY REFRIGERATING PROCESS AND THE APPARATUSAPPLICABLE THERETO Application filed. August 18, 1928, Serial No.300,505, and in Germany August 22, 1927.

My invention makes use of the compression and reexpansion of a gas,called the refrig erating medium to effect refrigeration. It may bepossible to utilize a permanent gas as a refrigerating medium, but stillin practice an alternating condensation and re-vapourization will beemployed almost exclusively; for the sake of simplicity, therefore, letthe refrigerating medium be assumed to be a vapour throughout thefollowing description. T his vapour, under suitably high temperature andpressure conditions in the condenser radiates heat into its surroundings(cooling water or air), by which means it is totally or partiallycondensed, and, owing to its expansion on account of loweredtemperature, extracts heat from the goods to be refrigerated directly orindirectly in the evaporator and is thereby totally or partiallyvapourized again; in this cycle the refrigerating medium must be raisedagain from a lower to a higher pressure between evaporator andcondenser. ing medium can also be absorbed after leaving the condenserin a so called absorber by a solvent heat being released and thenseparated again by heating in the generw tor; in this case the strongsolution has to be raised from the lower absorber pressure to the highergenerator pressure.

The above invention accomplishes the al ways necessary raising of amaterial from lower to higher pressure by a process specially safe inits operation. Its application, as said above, is particularly suitablefor small plants, i. e. for households or for the smaller industrialundertakings, in which case it is more a question of absolute safety inoperation and reliability in spite of any sort of unsuitable handling,than the utmost utilization of the power supplied; that, however, doesnot preclude its application under special conditions also for largerplants. For the achievment of this invention is great safety inoperation in that all packing glands and'similar constructional detailswhere the refrigerating medium might be able to escape or the air toenter are eliminated, and likewise all revolving or reciprocatingmachine parts, which are subject. to wear and tear;

The refrigeratfurther the process continues evenly without intermissionwhile an interrupted process requires switch mechanism, which musteither be operated by hand-and may be either wrongly operatedor.forgotten-or by automatic switch control gear, which from experienceis notably lacking in safety of operation, and is also costly. Moreover,in a case of failure of the cooling water, no dangerous pressure can beset up.

The invention fulfils these requirements in that it provides for thechange of pressure between evaporator and condenser by means of a jetcompressor. The power vapor necessary for operating the compressor .isgenerated in the power medium evaporator (hereinafter called briefly theboiler) after it has passed through the jet compressor giving ofi energyto the refrigerating medium, it is precipitated in the power mediumcondenser and flows back from there to the boiler, after the powermedium and refrigerating medium have separated one from the other. Thecondensation of the power medium and the refrigerating medium can beeffected jointly or in separate places, and the power medium can also becondensed before entering the compressor and the latter arranged as aliquid spray jet compressor. It is however always essential for theinvention that the power medium and also the refrigerating medium mustbe totally enclosed throughout their working cycle, that the powermedium condenser should be placed higher than the boiler, so that thepower medium can flow by gravity from the former to the latter, and thattwo kinds of material difiering one from the other are utilized forpower medium and refrigerating medium.

The mechanism of the so called steam refrigerator is well known; in thisthe working cycle is open and therefore refrigerating medium as well as.power medium must pass out into the open air and their loss compensatedelsewhere, for which purpose mechanically actuated parts and packingglands are necessary. Refrigerating plants with vapor injection and aclosed Working cycle in which the condenser pressure is equal to theboiler pressure are also well known;

even if. it is possible to-arrange the injection in such a way that thepower medium regains its initial pressure by virtue of its condensationthis class of apparatus always consumes a very eat uantity of drivingvapor, i. e., it is 0 low e ciency, and, moreover, the condensation hasto take' place at a higher pressure than is requisite, in other 'wor s,the refrigerating process must be carried on under unfavourableconditions. With another well known device, a second injector is usedfor returning the power medium to the boiler, but, apart from the factthat this means complication and increased cost of the plant, it has avery low degree of efiiciency, while the return by gravity of the aboveinvention has an efliciency of practically 100%, since the velocity ofthe returning liquid can be regulatedso slow that friction loss can beentirely neglected. Yet'again in another well known appliance gravity isutilized for return flow, but the same material is applied for power andre fri crating media. As the materials applicab e as refrigerating mediain as far as they admit of small pressure difference between evaporatorand condenser are comparatively light liquids, and since, to obtain areason ably favorable degree of efficiency, the boiler pressure on httoexceed the condenser pressure asmuc as possible, it follows that, withthis appliance, a very great construction.

. height is required, which generally is not the available, certainlynot in small plants and long pipe lines are also necessary, which reuthe compression principle but with two-stage compression and a commonboiler for both stages; Fig. 3 shows a similar arrangement as Fig. 2,except that for each pressure stage a separate boiler is provided. IFig. 4 shows an arrangement similar to that shown in Fig. 1, in whichthe evaporator is located at a higher level than the condenser; Fig. 5shows an arrangement operating on the absorption principle; Fig. 6 showsa similar arrangement in which the cooling medium successively assesthrough the condenser and the absor er. Fig. 7 also shows a similararrangement, in which the preheated air isused as combustion air for theboiler. Fig.

8 shows a similar arrangement as Fig. in WhlCh several et compressorsare connected in parallel; Figure 9 shows an arran ment similar toFigure 6 in which the. t rottl valve in the pipe connecting theevaporator v dium, f the condenser, c the throttle valve 1 for the poorsolution, it the burner for the boiler heater, is the boiler, m themixing 4 chamber of the jet compressor, n the generator, p the absorber,s the jet compressor, t the heat exchanger, u the blower, 'D theevaporator, w the condenser for the power medium, :1: the difference inthe height between the level of the liquid power medium in the condenserand in the boiler, y the difference in height between the levels of theliquid refrigerating medium in the evaporator and inthe condenser.

The arrangement shown in Fig. 1 operates as follows In the boiler k thepower medium, e. g. mercury, is evaporated (e. g. at a temperature of675 F.) by the application of heat (e. g.

by heating with a Bunsen burner h); the

vapour rises under the boiler pressure P;, (e. g. 14.6 lbs/sq. in.absolute) and flows with great velocity through the inlet nozzle I (Z ofthe jet compressor 8 into the mixing chamber 121.; cooling naturallytakes place in convertingv pressure into velocity which is veryopportune here. The pressure in the .mixing chamber P is somewhat lowerthan the evaporator pressure P so that the refrigerating medium (e.g.,water) is sucked up out of the evaporator 12. Refrigerating mediumand power medium enter the delivery--or outlet nozzle a together; herethe velocity is converted back largely into pressure, and both materialsenter the first collecting chamber or separator 6 under a pressure Pwhich is still lower than the boiler pressure P but afraction higherthan the con- I denser; pressure Pf of the refrigerating. me-

dium (e. g. 1 lb./sq. in. abs.) under'these circumstances partialcondensation may occur in the delivery nozzle, which iscompleted in thecondenser f. In'the construction. chosen as anexainple this consists oftwo parts, an upward air-cooled pipe coil f in which a great portion ofthe power medium precipitates at a relatively higher tem erature (e. g.between500 and 300 .F.), an a downward water-cooled pipe coil 7i inwhichthe refrigcrating medium is condensed (e. g. under a pressure of 0.96lbs/sq. in. and a temperature of 100 F.) The power medium collects forthe most part in the collecting chamberb a small residue in thecollecting chamber 6 in a fluid state on the bottom of the chamber, andflows from them back to the boiler k by gravity. In the example chosenthe difference in height between the levels of the liquids in chamber 6and in boiler is would have to be w=2 6". The refrigerating medium flowsfrom the second collecting chamber through the throttle or regulatingdevice e (which may be a valve, a narrow open-' in g or a narrow pipe)where it again expands to the evaporator pressure; in the evaporator vit is vapourized by extracting heat from the goods to be refrigeratedand is then sucked up again to the compressor. It is, as said above, notabsolutely necessary to condense the power medium and the refrigeratingmedium separately, as both can be condensed together, but in practicethe power medium should not be cooled off more than is necessary. Theplug marked 0 serves for filling up with power and refrigerating mediaand for removing air or other permanent gases and is kept tightly closedduring normal operation.

If a temperature lower than about 35 F.

must be obtained in the evaporator, then water naturally cannot beapplied as a liquid to be vapourized, as specified above; however, e. g.a solution of salts in water (such.

as chlorides of potassium, sodium, calcium, magnesium) or othermaterials (as e. g. sugar) can be fed to the evaporator as it freezes atlower temperatures; only the solvent of the solution vapourizes (as e.g. the water), as the evaporator pressure is correspondingly lower. Evenif small quantities of the material in solution are carried along, thiswill do no harm whatever, on the contrary their presence in thecondenser is quite advantageous because of the reduction of thepressure. Besides, such an addition of material in solution to therefrigerating liquid has a certain effect of regulation on its action;if for instance the supply output of the compressor is greater than thequantity flowing through the throttling device, the solution in theevaporator will become more concentrat ed, the vapour pressure will dropand with it very quickly the supply output of the compressor.

Other materials besides water and mercury can obviously be applied aspower and refrigerating media. But as, with the application of mercuryas a power medium, a variation of pressure of about lbs/sq. in. can beobtained with a difference of height of only 10', which is availablenearly anywhere, there is no reason why such materials as are usuallyapplied as refrigerating media and which work with a greater pressurevariation should not also be employed. The compression can also beeffected in two or more stages as shown in Figs. 2 and 3, and thecompressors mode of operation can be converted as to itsfirst stage fromjet injection to lgap action (Gaedes diffusion system), so t at anexceptionally low pressure can be maintained properly in the evaporator,enabling materials which are difficult to vapourize to be applied asrefrigerating medium. In principle, there is consequently hardly anyrestriction in the choice of refrigerating media. In practice, for thesake of safety, in all cases where such appliances are to be installedfor household use, those materials will always be chosen for preferencewhose condensation pressure is not con siderably above atmosphericpressure. An exceptionally high vacuum will also be avoided as a generalrule, because certain difiic'ulties occur in maintaining it properly,and penetration of air drastically lowers the efiiciency of the device.Further, these materials will generally be avoided that are in any waypoisonous or contain elements of danger by decomposition, explosion orcombustion, or which attack metals strongly, and, of course, powerandrefrigerating medium must be chemically neutral one as regards theother, and insoluble one with the other in the liquid state. There aresufficient suitable materials that comply with all these requirements.Also it is not absolutely necessary that the power medium be lessvolatile than the refrigerating medium. For example besides watermaterials can be used as a refrigerating medium as carbonic di-sulphideCS butane C H pentane C H hexane C H various alcohols, e. g.methyl-alcohol CILOH, ethyl-alcoholC H OH, and ether (CLH 0, thechlorine substitution products of the sebaceous order, e. g.methyl-chloride 011 61, carbon-tetrachloride GU1 and others or mixtures.

As power media carbon tetrachloride CCl or water may, for instance, beemployed; with these the necessary difference in height is indeedgreater than that for mercury,but even so this remains within manageablelimits, as long as the refrigerating medium is chosen to correspond.

Even if there is a failure of the cooling water or choking of thethrottling section, no inadmissible height of pressure can occur,because the jet compressor does not force in a continually sustainedquantity of refrigerating medium like a piston compressor, but, on thecontrary, its output decreases rapidly in proportion to increasingrecoil pressure, until it finally drops to zero.

Figs. 2 and 3 show two-stage arrangement of the jet compressor. Afterthe first stage, which produces an intermediate pressure, the powermedium is precipitated and fiows back -to the boiler, the refrigeratingmedium is further compressed in the second stage with some freshlyintroduced power medium. This kind of arranging the stages in series ismore economical than the arrangement whereby the evaporator of thehigher stage constitutes the condenser of the lower stage.

Naturally, either one or both stages can work with a liquid jet or alongthe diffusion system, and yet more than two stages can be provided, ifthe amount of pressure required demands this. A special boiler can be.provided to drive each stage, and according to circumstances, differentpower media as shown in Fig. 3. Also, if the quantity of power mediumrequired is too great, several nozzles can be provided side by side asshown in Fig. 8. With this arrangement of several boilers, either withsimultaneous or consecutive control, there is the advantage, that eachnozzle can be operated separately from the others without any controlmembers being provided in the pipes; this is a very desirable featurefor regulation when for example the required refrigerating effect varieswithin wide llmits, or when the condenser temperature or the evaporatortemperature required is subject to great change as, for instancesometimes only a cooling operation, some times the actual manufacture ofice is desired.

Figs. 2, 3 and 4 show'yet another variation. The expansion of therefrigerating medium from condenser to evaporator is not obtained hereby means of throttling, but by arranging the evaporator higher so thatthe liquid must be forced upwards against gravity. This has thefollowing advantage over the throttling method; the varying of thethrottling section by the handling of a valve as it is usual in largeplants shall be avoided here; or a narrow opening of fixedadjustment-quite apart from the fact that it is liable to be stopped upby dirt-allows only an absolutely fixed quantity to pass through with acertain pressure difference, and if the refrigerating effect and with itthe supply output of the compressor, and consequently also the quantityof the liquid passing through the throttling device be increased, allthis is only possible with a fixed throttle aperture, if at the sametime the condenser pressure is increased,,i. e. the process is carriedout under unfavourable conditions; with the arrangement above described.on the other hand, the

difference of pressure between condenser and evaporator is practicallyindependent of the quantity forwarded. Moreover, the refrigeratingliquid effects work to overcome gravity in rising from the condenser tothe evaporator; the compression is effected not by throttling. hutadiabatically, and it is well known that by this means the degree ofefficiency of the whole process is improved. For example, with theapplication of carbon tetrachlo ride as refrigerating medium, avapourizing temperature of 15 F. and a condensing tem perature of 100F., the evaporator pressure would be 9.37 lbs/sq. in., the condenserpressure 4 lbs./sq. -in.. consequently the pressure ratio 1:11 and thepressure difference 3.6 lbs/sq. in. In this case a two stage compressorwill be applied and the difference in height between evaporator andcondenser must be about y=5 9", because the specific ing vapour comingfrom the evaporator 10 is dissolved by a solvent in the absorber p. Thestrong solution after passing through the socalled heat exchanger t, israised by the jet pump 8 to the generator 11, while the power mediumflows back to the boiler, as in the other arrangements. The power mediumis condensed in this case by mixing with the solution. By this means notonly is the decrease in heat content which can be converted into kineticenergy very great, but also the solution on its way to the generator ispreheated. In the generator, the refrigerating medium is expelled fromthe solution by the application of heat, is then precipitated in thecondenser f and flows back to the evaporator '0 after throttling in 6,while the poor solution flows back through the heat exchanger t afterthrottling at g to the absorber, It follows, that in the absorptionprocess multistage compressors can also be applied.

In all types of construction care must be taken to employ the heatinggas and cooling water to the best advantage. for examplethe heatradiated from the boiler can be applied to a certain extent for heatingthe generator, or vice versa, aceordin to whether amore or less volatilepower me ium is applied (Fig. 5). The cooling medium (water or air)which primarily cools the condenser can flow from there to the absorber.

Where running water is not available, air cooling can also be provided,as shown in Figs. 6 and 7-. The cooling air can be employed in a similarway; the well heated cooling air can then serve partly as combustion airfor the heating flame of the boiler, as shown in Fig. 7.

As the heating gas even with the most efficient usage alwa-vs carriesoff a relatively high temperature in the exhaust pipe, it can beutilized by means of a suitable appliance (chimney) for. producing apowerful draught, and this, as shown in Figs. 5, 6 and 7, will carry thecooling air with it and ensure its proper circulation. (Blower u.)

\Vhat I claim is 1. The process of refrigerating, which consists inraising by jet compression a refrigerating medium dissolved in a solventfrom the lower absorbing pressure to the higher generating pressure,evaporating the power medium different from the refrigerating mediumprior to its work in the jetcompression, then condensing the same bymixing it with the solution, separating the power medium and thesolution by the agency of their different specific gravities, andpermitting the power medium to flow back to be again evaporated.

In this way,

2. The process of refrigerating, which consists in raising by etcompression a refrigerating medium dissolved in a solvent from the lowerabsorbing pressure to the higher generating pressure,evapprating thepower medium used-in the ct compression and different from therefrigerating medium prior to its work in the jet compression,condensing the power medium by mixing it with the solution, thenseparating the power medium and solution by the agency of theirdifferent specific gravities, and permitting the power medium to flowback by its specific weight to be again evaporated, while supplying heatby the same heating medium to the evaporating and generating elements.

3. The process of refrigerating, which consists in raising by jetcompression a refrigerating medium dissolved in a solvent from the lowerabsorbing pressure to the higher generating pressure, vaporizing thepower medium used in the jet compression and different from therefrigerating medium prior. to its work in the jet compression,condensing the power medium by mixing it with the solution, thenseparating the power medium and the solution by the agency of theirdifferent specific gravities, and finally permitting the power medium toflow back by its specific weight to be again evaporated, while coolingby the same cooling medium the condensing and absorbing elements.

4.. The process of refrigerating, which consists in raising by etcompression a refrigerating medium dissolved in a solvent from the lowerabsorbing pressure to the higher generating pressure, alternatelyvaporizing and condensing the power medium used in the jetcompressionand different from the refrigerating medium in a completely closedcycle, permitting the power medium to flow back by its specific weightto be again evaporated, while utilizing a portion only the cooling airafter having been preheated in the condensing operation ascombustion'air in the evaporating operation.

5. The process of refrigerating, which consists in raising by jetcompression a refrigerating medium dissolved in a solvent from the lowerabsorbing pressure to the higher generating pressure, alternatelyvaporizing and condensing the power medium used in the jet compressionand different from the refrigcrating medium in a completely closed cycleand permitting it to flow back by its specific weight to be againevaporated, causing a circulation of condensing cooling air, andutilizing a portion only of such air as combustion air in the vaporizingoperation.

6. A refrigerating apparatus, comprising an evaporator, a jetcompressor, a boiler having a vapor spaceconnected with the power mediuminlet nozzle of said compressor, a condenser connected with the pressurenozzle of said compressor, a separator connected with said condenser andthe liquid space of said boiler, and pipe conduits connecting saidcondenser with said evaporator, said condenser being disposed at aheight above said boiler to enable the power medium to flow back by itsspecific weight to said boiler, said evaporator being disposed at ahigher level than said separator to thereby cause the refrigeratingmedium to overcome the static pressure of a column of liquid on its waybetween said condenser and said evaporator.

7. A refrigerating apparatus comprising an evaporator, a jet compressor,an absorber connected therewith, a counter-current heat exchanger having'one chamber connected with said absorber and with the suction nozzle ofsaid jet compressor, a separator connected with the pressure nozzle ofsaid compressor, a boiler having a vapor space connected with the powermedium inlet nozzle of said compressor, the liquid space of said boilerbeing connected with said separator, a generator connected with saidseparator and with the other chamber of said counter-current heatexchanger, a throttling device connected with said heat exchanger andsaid absorber, connecting conduits between said generator and saidcondenser and between the latter and said throttling device, and pipeconduits connecting said throttling device with said evaporator, saidseparator being disposed at a height to enable the power mediumcollecting therein to flow back by its specific weight to said boiler.

8. The process of refrigerating, which consists in raising by jetcompression a refrigerating medium dissolved in a solvent from the lowerpressure to the higher generating pressure, evaporating the power mediumdifferent from the refrigerating medium prior to its work in the jetcompression, then condensing the same by mixing it with the solutionthen separating the power medium and solution by the agency of theirdifferent specific gravities, and permitting the power medium to flowback to be again evaporated while utilizing a portion only of thecooling air after having been preheated in the condensing and absorbingoperation as combustion air in the evaporating operation. 9. The processof refrigerating, which consists in raising by jet compression arefrigerating medium dissolved in a solvent from the lower pressure tothe higher generating pressure. evaporating the power medium differentfrom the refrigerating medium prior to its work in the jet compression,then condensing the same by mixing it with the solution then separatingthe power medium and solution by the agency of their different specificgravities and permitting the power medium 10. A refrigerating apparatuscomprising an evaporator, a jet compression, an absorber connectedtherewith, a counter-current heat exchanger having one chamber connectedwith said absorber and with the suction nozzle of said jet compressor, aseparator connected with the pressure nozzle of said compressor, aboiler having a vapor space con nected with the power medium inletnozzle of 10 said compressor, the liquid space of said boiler beingconnected with said separator, a gen erator connected with saidseparator and with the other chamber of said counter-current heatexchanger, connecting conduits between said generator and said condenserand between the latter and said evaporator, said separator beingdisposed at a height to enable the power medium collecting therein toflow back by its s ecific weight to said boiler,

-3 said evaporator ing disposed at a-higher level than said condenserthereby to cause the refrigerating medium to overcome the static ressureof a column of liquid on its way between said condenser and saidevaporator.

11. The process of refrigerating which consists in raising by jetcompression a refrigerating medium dissolved in a solvent from the lowerabsorbing pressure to the higher generatin pressure, evaporating apowermedia0 um di%erent from the refrigerating medium 7 prior to itswork in the jet compression, condensing the same by mixing it with thesolution separating the power medium and the solution by the agency oftheir diflerent spe- 4 a5 cific gravities' and permitting the powermedium to flow back by its specific wei ht be again vaporized, theevaporation 0% the refrigerating medium occuring at a higher level thanthe condensation. I 40 In testimony whereof I aflix my signature. ARTHURSELIGMANN.

